Production and Consumption of Hydrogen in a Eutrophic Lake

摘要: The vertical distribution of hydrogen was measured in the Loclat, a eutrophic and holomictic lake near Neuchâtel, Switzerland, before during summer stratification. H2 concentrations decreased with depth anaerobic hypolimnion were often below detection limit (2.5 nl liter−1) water adjacent to sediment. apparently not released from highest (>4 μl observed aerobic epilimnion metalimnion. There, changed time, indicating turnover H2. production processes could be studied laboratory since incubation samples light or darkness did result but rather always consumption. possible role cyanobacteria algae for is discussed. Aerobic consumption activities at all depths column, hypolimnion. activity insensitive azide inhibition, sensitive heat, mercuric chloride, cyanide. It restricted particle fraction 0.2 3.0 μm size, so that it must due single bacterial cells. bacteria, on other hand, occurred clusters >3.0 μm. Therefore, bacteria have caused water. followed Michaelis-Menten kinetics, Km 67 nM This an exceptionally low value compared values hydrogenases species, similar H2-decomposing abiontic soil hydrogenases.